The SNiP-LBT is a 'Sensor Node Integrated Package' for LoRaWAN or CAT-M1 communication of real-time leaf and bud temperature measurements, for continuous plant, light and environmental monitoring.
Frost damage to plants can have large impacts on crop yield and quality. Protection of crops during frost events is dependent on the accuracy of plant temperature predictions. Often, air temperature is not a reliable predictor of timing, duration and severity of frost events because plant canopy temperatures can be significantly different than air temperature under certain environmental conditions.
On clear, calm nights, plant leaf and flower bud temperatures can drop below freezing even if air temperature remains above 0°C. This is called a radiation frost and is due to the lack of air mixing (wind) near the surface, and a negative net longwave radiation balance at the surface (more longwave radiation is being emitted from the surface than what the surface is absorbing from the clear sky. Under cloudy and/or windy conditions, radiation frost events do not occur.
The SF-421 Leaf and Bud Temperature Sensor is a stainless steel sensor with SDI-12 communication protocol. The SF-421 has an SDI-12 digital output. The detector is a combination of two temperature sensors (precision thermistors) in a single housing. One sensor is designed to mimic a plant leaf the other a flower bud. The SF-421 provides close approximations to leaf and bud temperatures and has a temperature measurement range of -50 to 70°C.
Further parameters can be added to SNiP-LBT, without requiring loggers to match each distinct sensor, substantially reducing the cost of getting a fuller picture on the application.
The S-NODE (for Environmental Monitoring) has been designed to support the broad suite of SDI-12 based environmental sensors. The S-NODE can support sensors with higher power requirements; a solar panel can charge either the internal lithium-ion battery or both the node and sensor can be powered by an external 12V system (e.g. battery or mains source).
A decoder suitable for TTN will be provided based upon sensor configuration.
Typical applications include leaf and bud temperature estimates in cropped fields, orchards, and vineyards. Leaf and bud temperatures returned by the detector can then be used to alert growers to the potential of frost damage to crops. Sensor includes IP68 marine-grade stainless-steel cable connector 30 cm from head to simplify sensor removal and replacement for maintenance and recalibration.
|Measurement Range:||-50 to 70°C|
|Measurement Uncertainty:||0.1°C (from 0 to 70°C), 0.2°C (from -25 to 0°C), 0.4°C (from -50 to -25°C)|
|Measurement Repeatability:||Less than 0.05°C|
|Non-stability (Long-term Drift):||Less than 0.2°C per year (when used in non-condensing environments where the annual average temperature is less than 30°C; continuously high temperatures or continuously humid environments increase drift rate)|
|Equilibration Time:||10 s|
|Response Time:||Fastest data transmission rate for SDI-12 circuitry is 1s|
|Self-heating:||Less than 0.01°C|
|Operating Environment:||-50 to 70°C, 0 to 100% relative humidity|
|Input Voltage Requirement:||5.5 to 24 V DC|
|Current Drain:||0.6 mA (quiescent), 1.3 mA (active)|
|Dimensions:||570 mm length, 21 mm pipe diameter, 70 mm disk diameter|
|Cable:||5 m of two conductor, shielded, twisted-pair wire with santoprene rubber jacket (high water resistance, high UV stability, flexibility in cold conditions), additional cable available|
|Warranty:||4 years against defects in materials and workmanship|